A recent Blue Print technical blog explained why some Jeep/Chrysler models were ending up with air in the clutch hydraulic circuit that was not possible to purge, resulting in no clutch operation.

Problem
It is not possible to purge all of the air from the clutch hydraulic circuit. Therefore, resulting in no clutch operation.
 
Cause
The clutch hydraulic circuit is not equipped with a bleed nipple for purging the air, which may be trapped in the system.

Solution
The following procedure is a guide to bleeding the clutch hydraulic circuit to ensure correct operation.

The new clutch slave cylinder plunger, is fitted with a plastic retaining strap. DO NOT remove this strap prior to fitting. It is designed to retain the slave cylinder plunger until it is fitted, at which point it will break-free when operated for the first time, drawing fluid into the cylinder.

After fitting a new clutch hydraulic component, fill the clutch master cylinder reservoir with the manufacturer’s recommended fluid. Then pump the clutch pedal 60–100 times.

If the pedal still feels spongy or the clutch does not fully disengage, excessive air is still trapped within the system and you will need to perform the following procedure:

• Unbolt the clutch slave cylinder assembly from the transmission housing, but do not disconnect the hydraulic line.
• Note: DO NOT operate the clutch pedal whilst the slave cylinder is detached from the transmission housing, as this will damage the slave cylinder.
• Allow the slave cylinder to hang, making it the lowest part of the system.
• Depress the slave cylinder pushrod until it reaches its stop and then release. Repeat this at least 10 times, as this will force trapped air up and out of the system.
• Re-fit the slave cylinder to the transmission housing.
• Check and top up the clutch master cylinder, fluid level as necessary.
• Pump the clutch pedal 30 times. • If the pedal still feels spongy or the clutch still does not fully disengage, repeat the procedure until all air is purged from the system.

It is sometimes necessary to replace both the clutch master and slave cylinders in order to fully bleed this system. If you are only replacing one of them and are still experiencing difficulties after several attempts at purging air from the system, you may need to replace the other cylinder too.